This article is about 3 years old so it may be a bit out-of-date but perhaps it adds some information that you haven’t seen?
Lithium Ion vs. Lithium Polymer Batteries – Which Is Better? - RAVPower.
My own perspective on getting a desktop-like computer that doesn’t need a battery (other than for its clock!) and getting a battery-powered laptop is how much mobility you want in computing (and how big a screen). If you plan to move around a lot with a computer, you probably want a battery powered laptop, tablet, or 2-in-1 device. And perhaps it has to be light in weight, etc. If you plan to do most of your computer consumption in one place and like a big screen, maybe a desktop would be better (although you can use a docking station or a video cable of some sort to turn a small device into a big screen device).
I don’t know that they make many laptops these days with removable batteries but if I wanted the best of both, I think I’d get a laptop with a removable or replaceable battery: I’ve used my wife’s old 2011 clunker Gateway NV59 laptop for years on AC power with its removable battery stored in the refrigerator door “security” department in a loosely wrapped plastic bag at 45 deg F (and recharged a bit ~every 6 months after letting it warm to room temperature in its bag). According to the Gateway software, the battery charge capacity is still good as new - so 9 years later, I still have a portable computer with a brand new battery in it (when I actually want to be charging and discharging the battery).
As old as we are, though, any new computer and its battery may well outlast us and one could always take the view that having lived as long as we have, it’s time to treat oneself to the computational device(s) that one would most like to have and batteries, smatteries, just get what you want from a reputable computer maker, take reasonable care of the device (and maybe check out the possibility and the price of replacing whatever battery it has if needed someday down the line).